16 ohm speakers: any amp sounds better with more resolution. speaker cables less critical.
Am I missing something? In the video he didn't mention sound QUALITY at all. Nor any comment on AMP performance/distortion differences. His comments are about the SPEAKER, not the amp. He emphasizes, it's his choice for his high performance, high efficiency SPEAKERS . His demo is about loudness, saying 4 ohm will produce 3db more VOLUME than 8 ohm. IOW, it helps him with efficiency. |
atmasphere thanks for your clarity of these issues. I'm sticking with 16 ohm tap. remaining questions: 1. how importance is bias to sound? (I don't care about heat or tube life). ...................... 2. speaker cable inductance ..... gauge ____ awg mijostyn said " the wire you are using probably has high inductance. You should use 18 gauge wire that is a jacketed twisted pair like this". Guage: Cat 5 8 strands is 15 awg. Two Cat 5's, 16 strands, is 12 awg. https://www.wirebarn.com/Combined-Wire-Gauge-Calculator_ep_42.html I don't really understand inductance. If speakers are high efficiency (mine are), and I/you have more than enough power from the amp, speaker 3. equiv 15 awg, is inductance an issue? Inductance (Back EMF) might increase amount of current needed, but 4. enough power: does it have any effect on the music's frequencies? .............................. atmasphere Voltage/Current I read and re-read your paper you linked, http://www.atma-sphere.com/en/resources-paradigms-in-amplifier-design.html quite interesting. The Tekton video about using 4 ohm in lieu 8 ohms, 'getting more volume from 4 ohm' plays directly into your distinction between sensitivity and efficiency, which I never understood clearly before, thanks for that. That video also ignores feedback, distortion, current requirements. easy to be misinterpreted. ................................ Level Controls Electro-voice AT37 Attenuator's spec says 16 ohm; AT38 spec says 8 ohm. https://products.electrovoice.com/binary/AT37%20and%20AT38%20EDS.pdf EV instructions say start at 0 and cut from there. Zero as start, and positive numbers indicating more or even more attenuation (not boost) My level controls were evidently custom via Fisher: innards: exposed copper wound ceramic; exterior bronze finish recessed cup/handle for flush mount. A centered position, then boost or cut from that. The level controls are after the electro-voice 16 ohm crossover X336. Electro-voice crossovers were contained in a can filled with tar (smaller x36 shown), mine are 62 years old. https://products.electrovoice.com/binary/X6_X8_X425_X825_X36_X336_X2635_Engineering_Data_Sheet.pdf this shows X336 crossover and electro-voice attenuators AT37 used in various Electro-voice 3 way Speakers. https://www.ebay.com/itm/VINTAGE-EV-CROSSOVER-X336-2-PONTETIOMETR-CENTURION-VERY-CLEAN/274619211421?... ....................................... Components (anybody still awake?) All my speaker's components came from my uncle's Fisher 'President II Console I inherited, using electro-voice drivers and crossover. I have all the components, burned the wood in my fireplace. https://www.radiomuseum.org/r/fisher_president_ii_console_3000m.html Electro-voice speakers used their 15WK; Fisher chose the 15W https://www.ebay.com/i/114584280677?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&am... https://products.electrovoice.com/binary/15W,%2015BW,%2015WK,%2015BWK%20EDS.pdf Monster magnet, they weigh 37 lbs each. I've re-coned the woofers twice, I just checked, paper/cloth cone/coil kits still available. I have a spare 15W downstairs also. I replaced the original T35 horn with T350 which is +3db efficiency, useful as we age, nice to have the level control. http://www.cieri.net/Documenti/Istruzioni/Electrovoice%20-%20Tweeter%20T35,%20T35B,%20T350.pdf spare pair downstairs. the midrange is this crazy compound diffraction horn https://products.electrovoice.com/binary/847A%20EDS.pdf it looks like hell, but sounds terrific. spare downstairs ............................... These Level Controls give a lot of flexibility, BUT, it takes a lot of work getting both sides properly matched, the various sound positioning options of the McIntosh Mode Switch is the key my success. As frequencies change, i.e. you don't want certain piano notes left, others centered, others right. Imagine a singer's voice wandering. it's a big sigh of relief when you finally get it. |
lewm thanks for your thoughts. you know too much for my own good! level controls are in the neutral position now, i.e. doing nothing. I have been thinking of simply bypassing the level controls, on one speaker first, see how it compares with the other, any detectable changes. Then mess about with level controls other speaker, see if any 'improvement' can be found. No problem or better without the controls, then bypass the other. |
chakster
thanks. as usual, I wish you lived next door so I could hear your variety of speakers, equipment, .... 160 ohm resistor across the terminals. any idea what/why? |
McIntosh Speaker Wire Gauge/Distance/Resistance Chart (pdf pg 6) http://akdatabase.com/AKview/albums/userpics/10004/MC2250%20Owners.pdf Indicates: any given gauge: 8 ohm load allows double the length of a 4 ohm load. Presumably 16 ohm load would allow twice the 8 ohm allowable length (4 times allowable 4 ohm length). I have to believe many if not most are using larger gauge than needed, however, some with 4 ohm speakers that dip to 2 .. some people might not be using a large enough gauge. And people are overly concerned about long speaker cables. .............................. Text from my MC 2250’s manual: "Selection of the proper gauge wire to connect the loudspeakers to the amplifier preserves the quality of sound reproduction for which the loudspeakers have been designed. If undersize wire is used, resistance is added to the amplifier/loudspeaker combination which adversely affects the performance. Added resistance causes depreciation of damping characteristics, modification of frequency response and reduction in power to the loudspeaker. Use lamp cord or wire with similar insulation to connect the speakers to the amplifier. In all cases, the leads to and from the speaker should be twin parallel conductor or twisted pair. When using 8 ohm speakers and for the normally short distances of under 30 feet between the amplifier and speaker, #18 wire or larger can be used. For distances over 30 feet a larger diameter wire is required. Select the correct size from the chart below. The DC resistance of the speaker leads should be less than 5% of the speaker impedance. Resistance of the leads must be computed for the length of wire both to and from the speaker or speakers. Wire lengths above represent the wire resistance equal to 5% of the speaker impedance. For multiple speaker operation, run separate leads from the amplifier to the speakers." |
three_easy_payments
thanks, we agree about the video and advantages of 16 ohm reduced distortion. In the beginning, when 4 ohm speakers showed up, some sounded very good, however they were small enclosures, and it seemed to me they needed a heck of a lot of power, the complete opposite of my goals. I didn't know about amount of distortion involved. I encourage trying tube amps, and the way to save money/size/heat/cost of tube rolling/replacing, is to start with efficient speakers, thus you can stay in the 35/30/25 wpc world of tubes, even less if you use horn speakers or other highly efficient speakers. My friends system uses 8 wpc tube amps. I remodeled my office recently, my friend has an unused pair of KEF's, I remember them sounding great, I was going to use my Carver Cube 200wpc, enough power for them. However they are 15" deep (to get more box volume, avoiding port(s) I suppose), sadly too deep for bookshelf use. |
luisma31 everyone, This didn’t start about sound, I am completely content with everything as is. It was about bias controls, internal or external. I was considering changing to a newer version of this Cayin A88T tube amp to get external bias adjustment, which my current version lacks. Those newer versions have dropped the 16 ohm taps. Now that I have learned about the relationship of resistance to distortion, I’m sticking with this version, 16 ohm speakers to 16 ohm taps. Sticking with the internal bias controls. Steve at VAS previously said he would adjust the bias while I waited. https://vasnyinc.com/ He is only 1 hour away. Bill and I might go there together after the holidays. Meanwhile, I am going to bypass the level controls, expecting no change or better. thanks again, as always, for the shared experiences, friendly and knowledgeable advice. |
I’m gonna 1. remove the L pads another advantage: the L pads in the back panel won’t be wired to the crossover/drivers inside, the back will come fully off. 2. annual tightness check (nothing ever loose, but, to sleep better ..) a. confirm the drivers are tight to the front panel, and b. the front panel tight to the case c. 15" Woofer off the front panel, I can check the paper cone’s condition, it’s been several years. d. I might drill more mounting holes on the metal ring of the 15" woofer, 4 just doesn’t seem enough for that 37 lb monster (although it is never loose when I check) 3. make a new set of speaker cables using this: https://www.ebay.com/itm/75FT-CAT7-S-FTP-Network-Outdoor-High-Speed-10Gbps-Shielding-Ethernet-Cable-... OFC, S/FTP, 24 awg solid strands (8 conductors equivalent to 14 awg) (might be 26 awg, equivalent to 17 awg, waiting for seller's answer) 12 feet long each, (2+, 2- : 50 foot roll will just do it) 16 ohm nominal. McIntosh chart says 18 awg, 16 ohms, max 60 feet long. Unless someone talks me out of it!!! |
cisco, did you get #'s reversed? typical amp would be 12 wpc at 8 ohms, double at 4 ohms, i.e. 25 wpc at 4 ohms. If your transformer does not have a separate 16 ohm winding, then if you hook up a 16 ohm speaker to an 8 ohm tap, _____ wpc? sonically, this article says the mids would be boosted slightly http://blog.hughes-and-kettner.com/ohm-cooking-101-understanding-amps-speakers-and-impedance/ |
charles1dad on topic, what impedance are your speakers? off topic, I love trumpets! Wonderful and warm sounding trumpet! I'd love to hear you play live. Any recordings I could listen to? (send me a private message perhaps) Reading Raul, I was just thinking of when I heard Hugh Masekela live, sitting close in a very small club in NYC. Fantastic, did I say Fantastic. I have many Hugh recordings, highly enjoyable, but live ... I told him he was the best trumpet player ever. He replied, no, don't say that, looked at the ceiling, said there's a ghost of Louis Armstrong here, he was the best. The musical performances I choose to go to (used to go to) were chosen to hear someone live. I sit around here saying to Donna, it must be awesome to hear ... live. Even then, it's a stage, it's a mic, a sound system, yet there is Are you Korean? Just being funny, I spent several years watching Korean Dramas on Dramafever.com. Many times the parents were referred to (kid's name) ..... dad. Charles not the most common Korean name. regards, Elliott |
tomic601 thanks for ’cool dude’, I think more like ’old dude’ many must think ’long winded’. I ordered everything for new DIY Speaker Cables COST: $136.44 incl tax & delivery ................................. CONNECTORS (spades and adapters at speaker’s back panel) .........................................................spades, pure copper 2 set screws 8 pcs CABLE: I ended up ordering a cat8 s/ftp (shielded, foiled twisted pairs) When you twist them you lose length, I need 12 ft straight x 2 = 24’ x 2 spkrs = 48lf straight, a roll of 50ft would be short. Speaker cables l/r should always be the same length (time of travel aligned, hah!). I chose this cable, ordered 10 m (33ft) red; 10m (33ft) black, each leg 16lf to make 12 ft: red/black twisted. https://www.ebay.com/itm/174307181712 22 awg, 8 solid (not stranded) OFC copper S/FTP construction = 13 awg This chart shows relative gauges, physical sizes, and resistance. https://www.rapidtables.com/calc/wire/wire-gauge-chart.html two basic choices cat gauges: largest 22 awg; smallest 26 awg 22 awg x 8 = 13 awg (+152% area above 26 26 awg x 8 = 17 awg (+152% resistance above 22 22 awg solid = less flexible is not an issue for me. .......................................... CONDUCTIVITY CHART https://www.bluesea.com/resources/108/Electrical_Conductivity_of_Materials silver is only a little more conductive than copper gold and aluminum are only a little less conductive than copper brass is a lot less conductive than copper COPPER TYPES (hard to verify true facts) often text says solid but diagram shows stranded; text says 23 awg, chart shows 26 awg, and seller’s answers are often not clear. https://www.thomasnet.com/articles/metals-metal-products/types-of-copper-wire/ ’Pure Copper’, (99.9% pure) often in text, with or without OFC is not in the above article, it is in this article, https://en.wikipedia.org/wiki/Oxygen-free_copper C11000 - also known as Electrolytic-Tough-Pitch (ETP). This is the most common copper. It is universal for electrical applications. ETP has a minimum conductivity rating of 100% IACS and is required to be 99.9% pure. It has 0.02% to 0.04% oxygen content (typical). ................................... L PADS will be disconnected, new + wire direct from crossover for both horns (one as a test first) ............................ WOOFERS, remove, check cones Picking these suckers up onto a low bench for the work is a job for two masked men. Recent MRI: I now have 4 herniated discs, one tear, pinched nerve. |
charles1dad I just looked up your speakers. http://www.coincidentspeaker.com/total_eclipse.htm the diagram of the enclosure's internal bracing is beyond impressive. The 94 sensitivity is remarkable. my good friend has his custom designed speakers, that enclosure, that tweet/midrange arrangement, no woofers, no port. His mid is no doubt selected for more bass than yours. His sound fantastic, exceptional clarity, precise imaging, (only if centered) but he is always on the edge of wanting a sub, especially after listening to the same content here with my 15" woofers. Not only would I love to hear your speakers, I would love to listen to his, then get some masked brutes to put yours in the same place, hear the difference. With the enthusiasm of youth, to get 'more' from the 15" woofers (hah), I increased my enclosure volume from their original, AND added a rear port. Enclosure and tuned port co-designed with my AV Consultant (I designed Corporate Headquarters Boardrooms/Conference Centers/Video Conference rooms for 46 years) and Electrovoice Engineering department (they still existed in NYC then, extremely helpful) Great fun in prior location, but here, too much, not needed, closed the port. Because they are so space sensitive, and hearing Definitive Technology in showrooms when they were new in great, good, bad spaces, I advise avoiding ports and/or side firing, but in the right space I have heard some excellent results. If you move, new space??? I'm guessing you have a space that cooperates with them. |
OFC " only a one percent higher conductivity " (from this wiki OFC article) https://en.wikipedia.org/wiki/Oxygen-free_copper "Use in home audio The high-end speaker wire industry markets oxygen-free copper as having enhanced conductivity or other electrical properties that are supposedly advantageous to audio signal transmission. In fact, conductivity specifications for common C11000 (ETP) and higher-cost C10200 Oxygen-Free (OF) coppers are identical;[12] and even the much more expensive C10100 has only a one percent higher conductivity—insignificant in audio applications.[12] OFC is nevertheless sold for both audio and video signals in audio playback systems and home cinema.[12] " from the Copper Article https://en.wikipedia.org/wiki/Copper_conductor " The electrical conductivity of 6-nines copper and 4-nines copper (99.99% pure) is nearly the same at ambient temperature, although the higher-purity copper has a higher conductivity at cryogenic temperatures. Therefore, for non-cryogenic temperatures, 4-nines copper will probably remain the dominant material for most commercial wire applications.[3]" ....................................further 'covid reading' to follow |
Wish (where I found my pure OFC connectors) has huge 92% discount on some 3 meter high spec speaker cables https://www.wish.com/feed/tag_53dc186421a86318bdc87f20/product/5f8fe980bc9e0c03bab10189?utm_campaign... |
boothroyd Yes, I will be watching Steve, then do it myself after that. I dug out my Multimeter, took apart, cleaned it up with contact cleaner .. fresh batteries, and realized, I have no idea how to use it. Tandy, Micronta, 1990, I found the manual in my fat 'instructions' folder. You know I like Vintage stuff. What holes do I plug the cables in? What big center wheel setting? What adjust little pot to? I'm bringing it with me to Steve's. |
boothroyd thanks I was going to hook up my shop speakers, they are small 8 ohm, does it matter? is any load good enough? or, I avoid carrying the 55lb beast, just disconnect inputs, flip it on it's back, have at it. I've seen inside, took the cover off the hour I received it. Very impressive, and very spacious, easy to reach the contact points and adjusters. plangco here posted: 1. set his multi to 20V (as a preliminary setting, just to be in that range?; says spec is .4, he uses .35 to get longer tube life and slightly warmer sound. .4 what? how is .4 equal to 40 millivolts? is he saying start at 20, then increase to 20.4 or 20.35? I need brain surgery as previously discussed! |
L Pads are Staying! Full on mid and full on tweet ((similar to removing them) was not good! I messed about with them for quite a while. It is again clear to me that these speakers were designed with the control of mid to woofer and tweeter to mid in mind. The center position is their designed default, then carefully adjust. Then, as I have said, getting L and R matched is not easy, but I have my methods and experience with them in different spaces/locations for 43 years, especially using McIntosh Mode control to move stereo/mono/l/r this way and that. Next: Cassandra Wilson; Annie Lennox; Friday Night in San Fran 3 guitarists; Andreas Vollenweider; War of the Worlds. Rare Earth, Mickey Hart, Oscar Peterson. The advantages are clear, they have sounded fabulous all these years, using the controls in the listening space is an asset, and as I age, as my/our high frequency hearing naturally diminishes, I will be able to boost the tweeter year by year. |
I removed the L-Pads. I inspected the Woofers: Electrovoice 15W’s, 16 ohm from 1958. They have been re-coned twice so far, once a pro, 2nd time I did it! We have forced hot/cool air system. I suspected the left side woofer (near the heating vent) would be dried out, and it was. No holes, but paper was brittle. Other side surprisingly looked/felt an hour old. I put my re-coned spare in the left. I covered the heating vent temporarily, that will solve both heat and dust, I will buy a new register that opens/closes well, this one is from 1951, seals shot, hinge nasty. I'll have to see if it stays warm enough, and more importantly for me, cool enough in the summer. Of course opening it for cool air won't dry out the paper. now looking for a rebuild kit for Electro-voice 15W 16 ohm. Anyone know a source? thanks, Elliott |
